South Korean President Yoon Suk Yeol briefly declared martial law Tuesday amid alleged “anti-state” forces that he claimed were plotting rebellion and supporting North Korea, despite offering no evidence. 

But roughly six hours after Yoon called martial law and armed forces flooded the streets, the National Assembly voted to end the declaration. Yoon soon faced calls to resign or be impeached. However, an impeachment vote on Saturday failed due to a boycott from Yoon’s party, which was “apparently more concerned about a return to progressive leadership than about Yoon’s actions,” according to The Washington Post. But that seems to have only intensified protests, and the national police have opened an investigation into Yoon for treason. 

As the drama continues to unfurl, many Americans are now looking warily toward President-elect Donald Trump, trying to understand how something like this might play out in the states. 

Trump has a long history of admiring authoritarians. And in 2020, he deployed the National Guard to break up protestors in Washington, D.C., and Portland, Oregon, during protests over a police officer’s murder of George Floyd. But while controversial, that wasn’t martial law. 

However, Trump also reportedly asked about shooting those protestors but was stopped by skeptics in his administration. Which there will be fewer of this time around. And this year, he openly discussed the idea of deploying the military against “the enemy from within.”

A law expert who wished to remain anonymous told Daily Kos that while there is a small possibility that today's conservative-led Supreme Court would support the precedent of Trump declaring martial law, present concerns are “likely overblown.”

Still, ahead of Trump’s second administration, Daily Kos is taking a look at what martial law might look like—and has looked like—in the U.S. 

What is martial law?

Martial law is when the government approves military authority to temporarily step in for civilian government. It’s usually declared during times of war, rebellion, or natural disaster, per the Office of Justice Programs.

Essentially, what happens is that the military steps in to enforce laws and assist local governments in an area in place of local law enforcement. This can also include bringing people accused of crimes before military tribunals—where military officers function as the judge and jury—rather than civilian courts.

Has martial law been used in the U.S.?

Martial law has been declared at least 68 times in U.S. history, with the most recent federal declaration being made in the then-territory of Hawaii during World War II, according to the Brennan Center for Justice, a left-leaning public policy institute.

Following Japan’s devastating attack on Pearl Harbor, military officials were highly suspicious of Japanese-Hawaiians and often doubted their loyalty, journalist Erin Blakemore wrote for History.com. The three-year-long military rule created an oppressive living situation for Hawaiians, especially those of Japanese descent. 

While fear of a potential threat from Japan ran high, military control of food rations and a state-wide curfew made day-to-day living stressful as well. 

Even photography was banned in certain instances over fears of espionage.

Can a U.S. president declare martial law?

Probably not. 

A sitting U.S. president cannot declare martial law in the same way that Yoon did. In the U.S., the president needs approval from Congress first. 

However, as Joseph Nunn of the Brennan Center points out, laws surrounding the idea remain murky. Per Nunn’s article, a sitting president “has ample authority under current law to deploy troops to assist civilian law enforcement” (emphasis in original) but not necessarily replace it. 

That said, states can—and have—declared martial law more frequently, so long as a state’s declaration does not oppose the Constitution.

As Nunn points out, states have deployed military to step in at the local level to assist in things like natural disasters, which grants some power to military personnel on the ground. 

Nunn also told Daily Kos that the history of the United States’ founding goes against the premise of martial law, which was “part of the reason the American Revolution happened,” he explained.

“If you look at the Declaration of Independence, one of the charges that lay at the feet of King George is rendering the military power superior to the civilian [or enacting martial law] in the colonies,” he said. “So, everything about our constitutional system refutes the notion that martial law can exist.”

However, Nunn added that while martial law may be an overblown concern for Americans, the lack of limitations surrounding the Insurrection Act should have people concerned.

“The Insurrection Act gives the president virtually unlimited discretion to use the military as a domestic police force, even if they're operating in a supportive role [with local law enforcement],” he told Daily Kos. 

Nunn explains how “dangerous” it can be to send trained soldiers to act as police officers—a role far different from what they are trained to do in war zones. 

He argued that the president has “far too much discretion” over when to invoke the Insurrection Act, and that it gives “dangerously broad authority to the president to use the military as a domestic weapon.”

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